Start by preheating the oven to 350° F while you line two cookie sheets with parchment paper and set them aside.
In the bowl of a stand mixer, beat butter and ¾ cup of sugar using a paddle attachment on medium-high until light and fluffy (which usually takes around 2-3 minutes).
Add in the egg and vanilla to the butter and sugar mixture and beat on medium-high until well combined.
Combine flour, baking soda and salt in a small bowl. Carefully and slowly, add dry ingredients to wet ingredients and mix until just combined. Don't overmix.
Once the dough has formed, separate cookie dough into three even portions.
Place one portion of the dough back into the mixing bowl and add the red food coloring and mix until combined.
Wipe out the mixing bowl before adding another portion of dough and adding the blue food coloring and mixing that until combined.
Then, divide each dough ball into 12 even-sized pieces. Roll the small colored chunks into balls.
Gently and carefully, press one piece of each color dough together to create a ball with three distinct sections. Looking from the top, the ball should look like a pie cut into three large pieces.
Roll each tri colored cookie in the remaining two tablespoons of sugar and place them on the parchment-lined cookie sheets, leaving at least two inches between each cookie.
Bake cookies in the oven for 10-12 minutes, or until the edges are slightly golden.
Remove the cookies from the oven and allow cookies to cool on the cookie sheet for 5 minutes before transferring them to a wire rack to finish cooling.
Serve and enjoy.